This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-204888, filed Jul. 5, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a cooling unit for cooling heat generating components such as a semiconductor package and an electronic apparatus on which the cooling unit is mounted.
2. Description of the Related Art
For microprocessors for use in electronic apparatuses such as a portable computer, a heating value increases by an increase of a processing speed or an increase of functions. Therefore, a conventional electronic apparatus includes a cooling unit for forcibly cooling the microprocessor. One example of the conventional cooling unit is disclosed in xe2x80x9cJpn. Pat. Appln. KOKAI Publication No. 8-321571xe2x80x9d. The cooling unit includes a heat sink thermally connected to the microprocessor, and an electromotive fan incorporated in the heat sink.
The heat sink includes one air path through which air flows, an inlet positioned in an upstream end of the air path, and an outlet positioned in a downstream end of the air path. The air path is formed in the heat sink. The inlet is opened in an upper surface of the heat sink. The outlet is opened only in one side surface of the heat sink.
The electromotive fan includes an impeller. The impeller is disposed in the air path. When the impeller rotates, air is sucked into a rotation center portion of the impeller from the inlet, and the air is exhausted to the air path from an outer peripheral portion of the impeller by a centrifugal force. The air exhausted to the air path flows toward the outlet through the air path, and cools the heat sink in a flowing process. The air warmed by heat exchange with the heat sink is exhausted to the outside of the heat sink from the outlet.
In the conventional cooling unit, the air flowing through the air path in the heat sink functions as a major cooling medium to draw heat from the microprocessor. Therefore, a cooling capability of the microprocessor mainly depends on a flow rate of air which flows through the air path.
Additionally, according to the above-described conventional cooling unit, there is only one outlet for exhausting air, and the impeller is positioned in an end of the air path disposed opposite to the outlet. Therefore, a range extending substantially over the half of the outer peripheral portion of the impeller is disposed opposite to the inner surface of the air path. The exhaust of the air from the outer peripheral portion of the impeller is hindered by the inner surface of the air path. In other words, the air sucked into the rotation center portion of the impeller is exhausted to the air path from a partial range of the outer peripheral portion of the impeller, and the air cannot efficiently be exhausted from the entire periphery of the outer peripheral portion of the impeller.
Therefore, the flow rate of the air flowing through the air path cannot sufficiently be secured, and a problem occurs that the cooling capability of the microprocessor becomes insufficient.
An object of the present invention is to provide a cooling unit which can increase a flow rate of air flowing through an air path, and efficiently cool a heat generating component.
Another object of the present invention is to provide an electronic apparatus on which the cooling unit is mounted.
To achieve the above-described objects, according to a first aspect of the present invention, there is provided a cooling unit comprising: a fan having an outer peripheral portion for exhausting air; and a heat sink thermally connected to a heat generating component. The heat sink includes: a receptacle in which the fan is contained; a plurality of air paths which are arranged to surround the outer peripheral portion of the fan, and through which the air exhausted from the fan flows; and at least one partition which divides each air path into a plurality of regions. The partition extends toward a downstream of the air path from the outer peripheral portion of the fan.
According to the constitution, the flow of the air exhausted from the outer peripheral portion of the fan is not interrupted, and a flow direction of the air is not restricted to one. Additionally, since the air exhausted from the outer peripheral portion of the fan is guided by the partition and fed into the air path, the flow of air flowing through the air path is adjusted. Therefore, the air exhausted from the outer peripheral portion of the fan can efficiently be fed into the air path, and the flow rate of the air flowing through the air path increases.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.